FIG. 1 shows a conventional power converter that includes a power conversion circuit 10 to convert an input voltage (Vin) into an output voltage (Vout), and a digital controller 20 to adjust the output voltage (Vout). The digital controller 20 includes a comparator 21 receiving the output voltage (Vout) and a reference voltage (Vref) to generate an error voltage signal (e), an analog-to-digital converter (ADC) 22 to convert the error voltage signal (e) into an error digital signal (e[n:0]), a digital compensator 23 to generate a compensation signal (d[m:0]) based on the error digital signal (e[n:0]) for compensation of the difference between the output voltage (Vout) and the reference voltage (Vref), and a digital pulse width modulator 24 to generate a pulse width modulation (PWM) signal based on the compensation signal (d[m:0]) to control operations of transistors (PMOS, NMOS) of the power conversion circuit 10. To improve power consumption and operation efficiency of power converters is a goal in the relevant industry.